NEUROPATHOLOGY CORE SUMMARY The Neuropathology Core (NC) provides diagnostic services, sets up, and maintains a collection of brain samples, and supplies samples for research to investigators of the Center, affiliated Centers, and to outside neuroscientists conducting research into neurodegenerative diseases. Because humans are the only species to naturally develop AD the availability of postmortem samples for human tissue-dependent studies is essential despite the existence of transgenic animal models. We designed a standard protocol with built in flexibility to accommodate studies with specific aims, as the ones proposed by Project 3. Precisely identified samples, obtained from one half brain, are fresh frozen in liquid nitrogen vapor, and are electronically tracked. The contralateral half brain is used for 1)the diagnostic category, 2)teaching, and 3)research using formalin fixed samples. The postmortem findings are recorded within two standardized reports; a)text-based medical files, and b)quantification-based report, providing data to the Clinical Core/Data Management, and to NACC in compliance with NIA requirements. The categorization of both fresh frozen or fixed samples must be as accurate as possible. To optimize the diagnostic categorization a clinicopathological correlation is performed for each brain in collaboration with the Clinical Core. Once diagnostically categorized the postmortem brain samples are made available to neuroscientists quickly following receipt of a request. A subset of sample is provided to the Genetics Core for molecular dependent studies, and for the DNA library. Brain banking cannot be achieved at the cost of the teaching mission of academic institutions by routing brains away from residency programs when the autopsy rate is decreasing. Thus, while securing the standardization of processing, the evaluation of brains is combined with teaching the pathological changes of neurodegeneration to residents and fellows especially of the Pathology service. In contrast, emphasis on the differential clinical phenotypes of neurodegenerative diseases is achieved during the clinicopathological conferences, which are conducted monthly, with the Clinical Core and Education Core, and by caregivers involved directly with patients. Etty Paola Cortes Ramirez, MD, is a trainee participating in all tasks of the brain bank. Two Fellows, Drs. J. Valentin and H. Varma are in training including the neuropathology of neurodegenerative diseases. Renpei Sengoku,MD,PhD, learned in situ our methods of brain banking, and is implementing them at the Jikei University School of Medicine, Tokyo, Japan. We trained scientists and shared our experience and methods of processing brains and storing fresh frozen samples with the Southern Arizona VA Health Care System. We help implement our electronic tracking system at the National Prion Disease Pathology Surveillance Center- Case Western Reserve University, and at the Neuropathology and Prion Research Ludwig Maximilian University of M?nich.